Packaging Technologies for Temperature Sensing in Health Care Products

ABSTRACT

Temperature sensor packages and methods of fabrication are described. The temperature sensor packages in accordance with embodiments may be rigid or flexible. In some embodiments the temperature sensor packages are configured for touch sensing, and include an electrically conductive sensor pattern such as a thermocouple or resistance temperature detector (RTD) pattern. In some embodiments, the temperature sensor packages are configured for non-contact sensing an include an embedded transducer.

BACKGROUND Field

Embodiments described herein relate to microelectronic packaging, andmore particular to temperature sensor packaging technologies.

Background Information

Wearable health devices are increasingly integrating a broad variety ofsensors to better monitor heath status of users. With the development ofpackaging technologies such as system in package, embedded die,semiconductor very-large-scale integration (VLSI) technologies and so onit has become possible to develop miniaturized systems and devices. Skintemperature is one of the vital signs for patient's health.

SUMMARY

Temperature sensor packages, methods of fabrication, and productsincorporating such packages are described. For example, the temperaturesensor packages may be secured within (e.g. within a housing) of aportable electronic device, or secured to a fabric of a wearable device.The temperature sensor packages may be characterized as suitable fortouch or non-contact temperature sensing. In some embodiments, touchsensing configurations may be characterized as having a back sideelectrically conductive sensor pattern, where the electricallyconductive sensor pattern is over a back side of a chip (e.g. controllerchip for the package). In some embodiments, the touch sensingconfigurations may be characterized as having a front side electricallyconductive sensor pattern, where the where the electrically conductivesensor pattern on a front side of the chip. In some embodiments, anon-contact temperature sensor package may include an embeddedtransducer.

In an embodiment, a temperature sensor package includes a routing layer,a chip mounted face down on the routing layer, an insulating layerencapsulating the chip on the routing layer, a plurality of through viasthrough the insulating layer, and an electrically conductive sensorpattern over the insulating layer and coupled to the plurality ofthrough vias. The electrically conductive sensor pattern may be directlyover a back side of the chip. In an embodiment, the chip is solderbonded to the routing layer.

Various techniques may be used for the formation of the electricallyconductive sensor pattern and through vias. In some embodiments screenprinting or similar dispensing techniques are used. In an embodiment, atleast a portion of the electrically conductive temperature sensorpattern and at least one of the plurality of through vias is formed of asame material. In one implementation the same material includescoalesced metallic particles forming the portion of the electricallyconductive temperature sensor pattern and the one of the plurality ofthrough vias. In some embodiments laser direct structuring (LDS) isutilized. In one implementation the insulating layer is an LDScompatible material including a dispersed non-conductive metal organiccompound, and the plurality of vias include a nucleation layer of metalparticles of the metal in the dispersed non-conductive metal organiccompound. Similarly, the electrically conductive sensor pattern canoptionally include a nucleation layer pattern of metal particles of themetal in the dispersed non-conductive metal organic compound.

The electrically conductive sensor pattern have different modes ofoperation, such as thermocouple or resistance temperature detector (RTD)pattern. In an embodiment, the electrically conductive sensor pattern isa thermocouple pattern with a first pattern of a first conductivematerial and a second pattern of a second conductive material differentfrom the first conductive material. In an embodiment, the plurality ofthrough vias includes a first via connected to the first pattern, and asecond via connected to the second pattern. In a specificimplementation, the first via includes the first conductive material,and the second via includes the second conductive material, though thisis not required. In an embodiment, the electrically conductive sensorpattern is an RTD pattern, which may be formed of the same or differentmaterial than the plurality of through vias.

In an embodiment, a temperature sensor package includes a routing layerwith a chip contact area, and a touch area adjacent the chip contactarea. The touch area may include an electrically conductive sensorpattern electrically connected to the chip contact area, while a chip isbonded to the routing layer in the chip contact area. Such aconfiguration may be characterized as a front side electricallyconductive sensor pattern. In an embodiment, the chip is encapsulated inan insulating layer laterally surrounding the chip on a top side of therouting layer, and the insulating layer spans the touch area. In anembodiment, the chip is mounted on a first side of the routing layer,and a second side of the routing layer opposite the first side includesthe electrically conductive sensor pattern. In an embodiment, therouting layer includes a rigid-flex connection, the chip is mounted on arigid portion of the rigid-flex connection and the electricallyconductive sensor pattern is part of a flexible portion of therigid-flex connection.

In an embodiment, a temperature sensor package includes a routing layerincluding a top side and a bottom side, a cavity formed in the bottomside of the routing layer, a transducer mounted within the cavity, and achip mounted on the top side of the routing layer and in electricalconnection with the transducer. An optical window may be formed over asurface of the transducer. An insulating layer such as a moldingcompound may optionally encapsulate the routing layer and the chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a cross-sectional side view illustration of a temperature sensorpackage with embedded chip and front side electrically conductive sensorpattern in accordance with an embodiment.

FIG. 2 is a cross-sectional side view illustration of a temperaturesensor package with embedded chip and back side electrically conductivesensor pattern in accordance with an embodiment.

FIG. 3A is a schematic top view illustration of a resistance temperaturedetector (RTD) pattern in accordance with an embodiment.

FIG. 3B is a schematic top view illustration of a thermocouple patternin accordance with an embodiment.

FIG. 4 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 1 in accordance with an embodiment.

FIGS. 5A-5G are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 1 inaccordance with an embodiment.

FIG. 6 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 2 in accordance with an embodiment.

FIGS. 7A-7G are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 2 inaccordance with an embodiment.

FIG. 8 is a cross-sectional side view illustration of a temperaturesensor package with embedded chip and back side electrically conductivesensor pattern in accordance with an embodiment.

FIG. 9 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 8 in accordance with an embodiment.

FIGS. 10A-10H are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 8 inaccordance with an embodiment.

FIG. 11 is a cross-sectional side view illustration of a temperaturesensor package with embedded chip and back side electrically conductivesensor pattern in accordance with an embodiment.

FIG. 12 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 11 in accordance with an embodiment.

FIGS. 13A-13E are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 11 inaccordance with an embodiment.

FIG. 14 is a close-up schematic cross-sectional side view illustrationof a through via and electrically conductive sensor pattern layer formedusing laser direct structuring (LDS) and plating in accordance with anembodiment.

FIG. 15 a cross-sectional side view illustration of a temperature sensorpackage with embedded transducer for non-contact temperature sensing inaccordance with an embodiment.

FIG. 16 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 15 in accordance with an embodiment.

FIGS. 17A-17G are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 15 inaccordance with an embodiment.

FIG. 18 a cross-sectional side view illustration of a temperature sensorpackage with a chip mounted on a rigid-flex connection in accordancewith an embodiment.

FIG. 19 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 18 in accordance with an embodiment.

FIGS. 20A-20C are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 18 inaccordance with an embodiment.

FIG. 21 a cross-sectional side view illustration of a flexibletemperature sensor package in accordance with an embodiment.

FIG. 22 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 21 in accordance with an embodiment.

FIGS. 23A-23D are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 21 inaccordance with an embodiment.

FIGS. 24-25 are schematic side view illustrations of earbuds inaccordance with embodiments.

FIG. 26 are schematic side view illustrations of a wearable device inaccordance with an embodiment.

DETAILED DESCRIPTION

Embodiments describe temperature sensor packages, methods offabrication, and products incorporating such packages. In particular,embodiments describe temperature sensor packaging solutions that can beembedded into wearable heath devices for sensing temperature, such asskin temperature.

In one aspect, various touch sensitive temperature sensor packages aredescribed. Such packaging solutions may allow for integration intoflexible structures and do not require an optical window or transducerfor operation.

In an embodiment, a temperature sensor package includes a routing layer,a chip (such as a digital controller) mounted face down on the routinglayer, an insulating layer that encapsulates the chip on the routinglayer, and a plurality of through vias through the insulating layer. Anelectrically conductive sensor pattern such as a resistance temperaturedetector (RTD) pattern or thermocouple is located over the insulatinglayer and is coupled to the plurality of through vias.

In an embodiment, a temperature sensor package includes a routing layerthat includes a chip contact area and a touch area adjacent the chipcontact area. The touch area may include an electrically conductivesensor pattern electrically connected to the chip contact area, while achip is bonded to the routing layer in the chip contact area.

In another aspect, an infrared (IR) temperature sensor package isdescribed. Such a packaging solution may allow for space savings due toan embedded thermal sensor (e.g. transducer) and provide short andflexible routing. In an embodiment, a temperature sensor packageincludes a routing layer (e.g. circuit board) including a top side and abottom side. A cavity is formed in the bottom side of the routing layer,and a transducer is mounted is within the cavity. A chip is mounted on atop side of the routing layer and in electrical connection with thetransducer.

The routing layers in accordance with the various embodiments describedherein may be formed using various solutions such as redistributionlayers or printed circuit boards (PCBs), each including one or morewiring layers and dielectric layers. Furthermore, the routing layers maybe rigid or flexible, and in an embodiment may include a rigid-flexconnection.

In various embodiments, description is made with reference to figures.However, certain embodiments may be practiced without one or more ofthese specific details, or in combination with other known methods andconfigurations. In the following description, numerous specific detailsare set forth, such as specific configurations, dimensions andprocesses, etc., in order to provide a thorough understanding of theembodiments. In other instances, well-known semiconductor processes andmanufacturing techniques have not been described in particular detail inorder to not unnecessarily obscure the embodiments. Reference throughoutthis specification to “one embodiment” means that a particular feature,structure, configuration, or characteristic described in connection withthe embodiment is included in at least one embodiment. Thus, theappearances of the phrase “in one embodiment” in various placesthroughout this specification are not necessarily referring to the sameembodiment. Furthermore, the particular features, structures,configurations, or characteristics may be combined in any suitablemanner in one or more embodiments.

The terms “over”, “to”, “between”, “spanning” and “on” as used hereinmay refer to a relative position of one layer with respect to otherlayers. One layer “over”, “spanning” or “on” another layer or bonded“to” or in “contact” with another layer may be directly in contact withthe other layer or may have one or more intervening layers. One layer“between” layers may be directly in contact with the layers or may haveone or more intervening layers.

Referring now to FIG. 1 a cross-sectional side view illustration isprovided of a temperature sensor package 100 with an embedded chip 110and front side electrically conductive sensor pattern 120 in accordancewith an embodiment. As illustrated, the temperature sensor package 100can include a routing layer 130 that includes a chip contact area 132and a touch area 134 adjacent to the chip contact area 132. In theillustrated embodiment, the touch area 134 includes the electricallyconductive sensor pattern 120 that is electrically connected to chipcontact area 132 and chip 110 that is bonded to the routing layer 130 inthe chip contact area 132.

The chip 110 may be any type of controller chip for operation of thetemperature sensor package 100, such as a digital IC, analog IC, mixeddigital and analog IC, and may include additional circuitry such as anintegrated amplifier. In accordance with embodiments, the chip 10 iselectrically connected with the electrically conductive sensor pattern120.

The routing layer 130 may include one or more dielectric layers 142 andwiring layers 144, and optionally vias 146. As shown, the chip 110 canbe encapsulated in an insulating layer 140 on a top side 136 of therouting layer, while the bottom side 138 of the routing layer 130includes the electrically conductive sensor pattern 120. The insulatinglayer 140 may be formed of a variety of materials such as an adhesivebonding or flexible molding compound and may additionally span the toucharea 134 on the top side 136 of the routing layer 130. Exemplarymaterials include, but are not limited to, benzocyclobutene (BCB),epoxy, silicone, epoxy-based photoresist such as SU-8, etc. A top sidepassivation layer 150 can be formed over the chip 110 and insulatinglayer 140. For example, the top side passivation layer 150 may be aflexible polymer, such as polyimide. In addition to providingpassivation function, the top side passivation layer 150 can be used totune flexibility of the temperature sensor package 100. Likewise, theone or more dielectric layers 142 may be used to tune flexibility, inaddition to providing an insulating substrate for the electricallyconductive sensor pattern 120. The one or more dielectric layers 142 mayoptionally be formed of similar materials as the top side passivationlayer 150. In accordance with embodiments, insulating layer 140 mayprovide both sealing features, and under-filling structure for thestack-up.

A temperature sensor package 100 such as that illustrated in FIG. 1 mayprovide a flexible encapsulated structure, which enables embedding thechip 110 into a flexible stack without a need for optical window ortransducer since the electrically conductive sensor pattern 120 can beformed as part of the bottom side of the routing layer 130.

The temperature sensor package 100 can additionally be characterized ashaving a front side connection in which the electrically conductivesensor pattern 120 is adjacent a front side 111 of the chip 110.Furthermore, the electrically conductive sensor pattern 120 is formed onan opposite side of the routing layer 130 than the chip 110. As shown,the chip 110 is on a first side (e.g. top side 136) of the routing layer130, while the electrically conductive sensor pattern 120 is on, or apart of, a second side (e.g. bottom side 138) of the routing layer 130opposite the first side 136. In an embodiment, the routing layer 130 isformed directly on the front side 111 of the chip 130. For example,wiring layers 144 or vias 146 may be formed directly on chip contactpads 112. Similarly, the electrically conductive sensor pattern 120 maybe formed directly on routing contacts 148, such as with the wiringlayers 144 or vias 146 on an opposite side of the routing layer 130.

FIG. 2 a cross-sectional side view illustration of a temperature sensorpackage 100 with embedded chip 110 and back side electrically conductivesensor pattern 120 in accordance with an embodiment. A shown, thetemperature sensor package 100 can include a routing layer 130, a chip110 mounted face down on the routing layer 130, an insulating layer 140encapsulating the chip on the routing layer 130, and a plurality ofthrough vias 160 through the insulating layer 140. For example, thethrough vias 160 may extend between a first (e.g. top) surface 143 andsecond (e.g. bottom) surface 141 of the insulating layer 140 to makecontact with the routing contacts 148 of the routing layer 130. In theillustrated embodiment, an electrically conductive sensor pattern 120 isformed over the insulating layer (e.g. over the top surface 141) and iscoupled to the plurality of through vias 160. Furthermore, theelectrically conductive sensor pattern 120 may be directly over a backside 113 of the chip 110.

The electrically conductive sensor pattern 120 may be formed of one ormore materials and may be formed of the same or different materials thanthe plurality of through vias 160. In an embodiment, at least a portionof the electrically conductive temperature sensor pattern 120 and atleast one of the plurality of through vias 160 is formed of a samematerial. The particular material may be dependent upon method ofmanufacture, such as plating (electroplating, electroless plating),printing, dispensing, etc. For example, plating techniques may includeseed and bulk layers, while printing or dispensing techniques mayinclude a matrix of coalesced metallic particles (which may be mixedwith an adhesive such as polymer or glass).

Referring now to FIGS. 3A-3B the electrically conductive sensor pattern120 may have a variety of different shapes depending upon function. Forexample, FIG. 3A is a schematic top view illustration of an exemplaryresistance temperature detector (RTD) pattern, while FIG. 3B is aschematic top view illustration of an exemplary thermocouple pattern inaccordance with embodiments. Referring now to FIG. 3A, an electricallyconductive sensor pattern 120 in the form of an RTD pattern may includea single conductive layer 122 (or layer stack). For example, this may bea metal layer, or metal stack, or layer of coalesced metal particles forexample. The conductive layer 122 may be formed of the same material ora different material than the through vias 160 of FIG. 2, for example.Referring to FIG. 3B, the electrically conductive sensor pattern 120 inthe form of a thermocouple pattern may include a first layer 122 patternof a first conductive material and a second layer 124 pattern of asecond conductive material different from the first conductive material.For example, these can be different metal layers with differentresistances. The first and second layers 122, 124 may be formedseparately from, or with the corresponding through vias 160. In anembodiment, a first through via 160 includes a first conductive materialof the corresponding first layer 122, and the second through via 160includes a second conductive material of the corresponding second layer124. For example, a dispensing technique can be used to form theconductive layers and vias of the same material. After driving off ofsolvent and annealing such a dispensed pasted or solution may result ina body of coalesced metallic particles (which may be mixed with anadhesive such as polymer or glass).

The temperature sensor packages 100 of FIGS. 1-2 may share severalcommon features, though be formed using different fabrication sequences.Each fabrication technique may include coating of an electrical gradepolymer such as polyimide, and placement of active and/or passivecomponents (including the chip 110) on the electrical grade polymer. Thecomponents can then be encapsulated using a flexible bonding material,and a second electrical grade flexible polymer can be formed on theencapsulated structure. An electrically conductive sensor pattern 120(e.g. metallization layer) can then be formed.

FIG. 4 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 1 in accordance with an embodiment. FIGS. 5A-5Gare schematic cross-sectional side view illustrations of a method offabricating the temperature sensor package of FIG. 1 in accordance withan embodiment. In interest of clarity and conciseness the processingsequences of FIGS. 4 and 5A-5G are described concurrently.

At operation 4010 a top side passivation layer 150 is formed. As shownin FIGS. 5A-5B, this sequence may include preparing a rigid carriersubstrate 200 with an adhesive layer 202 such as a tape, followed byapplication of the top side passivation layer 150. For example, top sidepassivation layer 150 may be laminated, or deposited and cured. Atoperation 4020 the chip 110 is placed faced up on the top sidepassivation layer 150 as shown in FIG. 5C using a suitable techniquesuch as a pick and place tool. Referring now to FIGS. 5D-5E, atoperation 4030 the chip 110 is encapsulated in an insulating layer 140,followed by formation of routing layer 130 on the chip 110 andinsulating layer 140 at operation 4040. Depending upon application, theinsulating layer 140 may be a flexible material, though this is notrequired. Materials used for top side passivation layer 150, anddielectric layer(s) 142 of routing layer 130 may be electrical grade,and may also be flexible. The electrically conductive sensor pattern 120may then be formed at operation 4050, followed by removal of theadhesive layer 202 and rigid carrier substrate 200 as shown in FIGS.5F-5G. The electrically conductive sensor pattern 120 may be formedusing a variety of suitable techniques such as printing or otherdispensing technique, physical or chemical vapor deposition, andplating.

FIG. 6 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 2 in accordance with an embodiment. FIGS. 7A-7Gare schematic cross-sectional side view illustrations of a method offabricating the temperature sensor package of FIG. 2 in accordance withan embodiment. In interest of clarity and conciseness the processingsequences of FIGS. 4 and 7A-7G are described concurrently.

At operation 6010 a chip 110 is mounted on routing layer 130. In theparticular sequence illustrated in FIGS. 7A-7C, a rigid carriersubstrate 200 with an adhesive layer 202 such as a tape, followed byapplication or formation of the routing layer 130. The routing layer 130may be laminated, or alternatively formed using a thin film fabricationsequence of deposition and patterning dielectric layer(s) 142 andconductive (e.g. metallization) layers to form wiring layers 144, andoptionally vias 146. The chip 110 can be mounted onto the routing layer130 using a suitable technique such as pick and place with solder bumps114, which may be bonded to routing contacts 148 for example.

Referring now to FIG. 7D, the chip 110 may optionally be underfilledfollowed by encapsulation with an insulating layer 140 at operation6020, followed by the formation of an optional top side passivationlayer 150. Depending upon application, the insulating layer 140 may be aflexible material, though this is not required. Materials used for topside passivation layer 150, and dielectric layer(s) 142 of routing layer130 may be electrical grade, and may also be flexible.

Via openings 145 are then formed through the insulating layer 140 toexpose the routing layer 130 at operation 6030. Where top sidepassivation layer 150 is present, the via openings 145 can additionallybe formed through the top side passivation layer 150. Via openings 145may be formed using patterning techniques such as laser, drilling, orchemical etching.

Referring now to FIG. 7F, electrically conductive through vias 160 arethen formed within via openings 145 at operation 6040, and anelectrically conductive sensor pattern 120 is formed at operation 6050.Operations 6040 and 6050 may be performed sequentially or simultaneouslyin accordance with embodiments. Furthermore, one or more same ordissimilar materials may be used to form the through vias 160 andelectrically conductive sensor pattern 120. Thus, the through vias 160and electrically conductive sensor pattern can be formed of the samematerials or different materials and may be formed simultaneously (whensame materials) or sequentially. Suitable materials include nickel,copper, platinum and conductive pastes that may include conductiveparticles that can be annealed or sintered together to form a coalescedbody of particles. Exemplary deposition techniques include screenprinting or other dispensing techniques, physical or chemical vapordeposition, and plating. In an embodiment, the temperature sensorpackage 100 includes a pair of through vias 160, each through via 160having a different composition. For example, such as configuration maybe used with a RTD pattern including layers 122, 124 formed of differentmaterials (e.g. metals).

In the following description numerous temperature sensor packages 100and methods of fabrication are described. In particular, the temperaturesensor packages 100 may be variations of the temperature sensor packages100 described and illustrated with regard to FIGS. 1-2. Accordingly,like features share the same reference numbers, and related descriptionsmay not be repeated in order to avoid unnecessarily obscuring theembodiments.

FIG. 8 is a cross-sectional side view illustration of a temperaturesensor package 100 with embedded chip 110 and back side electricallyconductive sensor pattern 120 in accordance with an embodiment. Inparticular, FIG. 8 shares many structural similarities to the embodimentillustrated and described with regard to FIG. 2, with one variationbeing that the temperature sensor package 100 of FIG. 8 can beconsidered a substrate-less, and in particular the routing layer 130 maybe substrate-less. In an embodiment, routing layer 130 may be a singlewiring layer 144, and not include additional dielectric layers. Similarto FIG. 2, the temperature sensor package 100 of FIG. 8 may optionallybe a flexible stack-up.

FIG. 9 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 8 in accordance with an embodiment. FIGS. 10A-10Hare schematic cross-sectional side view illustrations of a method offabricating the temperature sensor package of FIG. 8 in accordance withan embodiment. In interest of clarity and conciseness the processingsequences of FIGS. 9 and 10A-10H are described concurrently.

As illustrated in FIG. 10A the sequence may begin with a bottom sidepassivation layer 300 on a rigid carrier substrate 200. For example, thebottom side passivation layer 300 may be formed using a suitabletechnique such as lamination or deposition. The bottom side passivationlayer 300 may be formed of similar materials as top side passivationlayer 150 previously described. At operation 9010 a routing layer 130 isformed on the bottom side passivation layer 300 as shown in FIG. 10B. Inan embodiment, the routing layer 130 includes a single metallizationlayer or wiring layer 144, which can be formed using a variety oftechniques such as screen printing or other dispensing method, physicalor chemical vapor deposition, and plating. Screen printing or otherdispensing methods in particular may be particularly simple formanufacturing.

Referring to FIGS. 10C-10D, in either order, at operation 9020 aninsulating layer is formed on the routing layer 130, and at operation9030 a chip 110 is mounted on the routing layer 130. In the particularsequence illustrated the insulating layer 140 can be formed prior tomounting the chip 110, though the order can be reversed. Insulatinglayer 140 may be formed of any materials previously described for theinsulating layer 140 and may be deposited using a suitable techniquesuch as spraying or other coating technique. In such a sequence, thechip 110 can be mounted prior to curing the insulating layer 140.Alternatively, a cavity can be etched into the insulating layer 140prior placement of the chip 110. In yet another embodiment, the chip 110can be mounted prior to formation of the insulating layer 140.

The processing sequence illustrated in FIGS. 10E-10H may then proceedsimilarly as that illustrated and described with regard to FIGS. 7D-7G.In particular, a top side passivation layer 150 can be formed, followedby formation of via openings 145 through the insulating layer 140 (andtop side passivation layer 150 if present) to expose the routing layer130, or specifically wiring layer 144. Either sequentially orsimultaneously, the electrically conductive through vias 160 are formedwithin the via openings 145 and the electrically conductive sensorpattern 120 are formed at operations 9050 and 9060.

FIG. 11 is a cross-sectional side view illustration of a temperaturesensor package 100 with embedded chip 110 and back side electricallyconductive sensor pattern 120 in accordance with an embodiment. Inparticular, FIG. 11 shares many structural similarities to theembodiment illustrated and described with regard to FIG. 2, with onevariation being that the temperature sensor package 100 of FIG. 11 canbe fabricated using laser direct structuring (LDS). In an embodiment,the insulating layer 140 is an LDS compatible material including adispersed non-conductive metal organic compound, and the electricallyconductive through vias 160 may be defined using LDS. Specifically, theplurality of through vias 160 can include a nucleation layer of metalparticles of the metal in the dispersed non-conductive metal organiccompound. Similarly, the electrically conductive sensor pattern 120 caninclude a nucleation layer pattern of metal particles of the metal inthe dispersed non-conductive metal organic compound.

FIG. 12 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 11 in accordance with an embodiment. FIGS.13A-13E are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 11 inaccordance with an embodiment. In interest of clarity and concisenessthe processing sequences of FIGS. 12 and 13A-13D are describedconcurrently.

Referring now to FIG. 13A, at operation 1210 a chip 110 is mounted ontothe routing layer 130. It is to be appreciated that additionalcomponents 180 can also be similarly mounted in all embodimentsdescribed herein. For example, one or more components 180 may be passivedevices such as capacitors, etc. used for chip 110 (e.g. digital IC). Inan embodiment, routing layer 130 is a printed circuit board (PCB), whichmay optionally be a rigid substrate. The chip 110 and optionalcomponent(s) 180 are then encapsulated in an insulating layer 140 atoperation 1220. In accordance with embodiments, the insulating layer 140may be an LDS compatible material. It is to be appreciated that whilecomponents 180 are only described and illustrated with regard to theembodiment of FIG. 12 that the components 180 can be similarlyintegrated adjacent the chips 110 in all other embodiments describedherein.

LDS compatible molding compounds in accordance with embodiments mayinclude a matrix material, and an LDS additive dispersed in the matrixmaterial. For example, the LDS additive may be a non-conductive metalorganic compound. This may include a variety of metal oxidecompositions, which may be compounded with (e.g. complexed) with thematrix material (e.g. resin). In an exemplary embodiment, the LDSadditive is a dispersed tin oxide composition that is complexed with thematrix material. Embodiments are not limited to tin oxide, and a varietyof other non-conductive metal organic compounds may be used, includingother compounded metal oxides.

A variety of organic materials can be used for the matrix material,which may be dependent upon temperature exposure. Low temperaturesmaterials include polycarbonate (PC) and acrilonitrile butadiene styrene(ABS). Medium temperature material that can withstand solderingtemperatures include polycaprolactam (PA6/6) and polyphthalamides (PPA).A higher temperature material that can withstand virtually any solderingpolyether ether ketone (PEEK). Other suitable material may includepolypropylene (PP), polyethylene terpthalate (PET), polybutyleneterpthalate (PBT), polyphenylene sulfide (PPS), and liquid crystalpolymers (LCP).

At operation 1230 the via openings 145 are laser defined in theinsulating layer 140. The LDS additive, and laser parameters areselected so that upon application of the laser to the molding compound,the elemental metal in the non-conductive metal organic compound breaksfrom the compound and forms nucleation particles within a nucleationlayer 1410 forming a conducting path corresponding to the laser pattern.As shown, the nucleation layer 1410 may line the sidewalls of the viaopenings 145. Optionally, the laser process may be applied to the topsurface 143 of the insulating layer 140 to additionally definenucleation layers 1412 that can subsequently be used to form theelectrically conductive sensor pattern.

In accordance with embodiments, the through vias 160 can be created bylaser followed by filling the via openings 145 formed by the laserprocess at operation 1240 by plating or dispensing of a conductive paste(e.g. silver-based epoxy) as a bulk layer 1420 into the blanked viaopenings 145. The electrically conductive sensor pattern 120 may then beformed on the insulating layer at operation 1250. As previouslydescribed, the electrically conductive sensor pattern 120 may be formedof the same or different materials than the through vias 160, and may beformed sequentially or simultaneously. In an embodiment, theelectrically conductive sensor pattern 120 is an RTD pattern of samecomposition (e.g. single metal layer, or metal stack). In an embodiment,the electrically conductive sensor pattern 120 is a thermocouple patternincluding dissimilar metallic layers 122, 124. FIGS. 13D-13E illustratesuch a processing sequence. In an embodiment, the electricallyconductive sensor pattern 120 is formed using a screen printing,dispensing or selective plating technique. In an embodiment, the seedlayers 1412 can be utilized for a plating sequence for the formation oflayers 122, 124. Thus, seed layers 1412 may be formed of a samematerial, for dissimilar layers 122, 124. Various metal layers can beformed with the plating process including gold, nickel, silver, zinc,tin, platinum, platinum-rhodium alloy, iron, iron-copper alloy,copper-nickel alloy, etc. FIG. 14 is a close-up schematiccross-sectional side view illustration of a through via 160 andelectrically conductive sensor pattern 120 and layer 122 formed usingLDS and plating in accordance with an embodiment.

Up until this point, the described embodiments have been directed totouch-sensitive temperature sensor packages 100 where the electricallyconductive sensor pattern 120 can form a portion of the sensing surfacefor the package. FIG. 15 a cross-sectional side view illustration of atemperature sensor package with embedded transducer for non-contacttemperature sensing in accordance with an embodiment. In accordance withembodiments, embedding the transducer may provide save spacings.Additionally, short and flexible routing can be provided between thetransducer and chip 110 for integration into different subsystems fornon-contact temperature sensing.

In an embodiment, a temperature sensor package 100 includes a routinglayer 130 (e.g. PCB) including a top side 136 and a bottom side 138, acavity 190 formed in the bottom side 138 of the routing layer 130, and atransducer 400 mounted within the cavity 190. A chip 110 is mounted onthe top side 36 of the routing layer and in electrical connection withthe transducer (e.g. with routing layers 144, vias 146, etc.). Aninsulating layer 430 may encapsulate the transducer 400 within thecavity 190, optionally leaving a surface 401 exposed though this is nota strict requirement.

While not separately illustrated, an interposer (e.g. glass) or a lowthermal conductive under-fill material can be used to provide thermalisolation between the chip 110 (e.g. digital IC) and the routing layer130.

In an embodiment, the transducer 400 is an infrared (IR) sensor thatmeasures temperature by receiving radiant heat from an object. Forexample, the transducer 400 may be a thermopile-basedmicroelectromechanical systems (MEMS) IR sensor. Such sensors may be assmall as a few hundred microns, and may additionally include a signalconditioner to convert an analog output from the thermopile into adigital input for the chip 110. The temperature sensor package 100 mayadditionally include an optical window 420 over a surface of thetransducer. For example, the optical window 420 may be transparent tothe IR wavelength, and optionally filter out other wavelength ranges toreduce noise. The optical window 420 may include multiple layersincluding a separate wavelength range filter layer. Alternatively, thetransducer 400 may be designed to be responsive to another wavelengthrange (e.g. visible, etc.). Similarly, the optical window 420 may bedesigned to be transmissive to the operable wavelength range, andoptionally filter out non-operable wavelengths.

The chip 110, routing layer 130, and thermal sensor arrangement may besecured inside an enclosure 450 in an embodiment. Enclosure 450 can bemade of metal shield, glass, rigid plastic (like epoxy, polycarbonate,polyethylene), soft plastic (silicone, thermoplastic), etc. Theenclosure can have on opening 452 in correspondence of the transducer400, or such an opening 452 may not be needed when a materialtransparent to IR is used, like sapphire, silicon, fused silica,polycarbonate or acrylic. In an embodiment, the optical window 420 isarranged within an opening 412 in dielectric layer 410 formed on thebottom side 138 of the routing layer 130. The dielectric layer 410 mayin turn be secured to the enclosure 450, with the optional opening 452in the enclosure arranged over the optical window 420. In theillustrated embodiment, the chip and routing layer can be surrounded(including laterally surrounded) by an open space 455 within theenclosure 450. Alternatively, the open space 455 may be replaced with aninsulating layer 140 that encapsulates the chip and routing layer. In anembodiment, insulating layer 140 is present without the enclosure 450.

In operation, the temperature sensor package 100 of FIG. 15 can belocated at a working distance from a source, such as body skin of atarget subject, allowing constant temperature monitoring. Physicalcontact between the source and temperature sensor package 100 is notrequired.

FIG. 16 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 15 in accordance with an embodiment. FIGS.17A-17G are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 15 inaccordance with an embodiment. At operation 1610 a transducer 400 ismounted within a cavity 190 formed in a routing layer 130. Routing layer130 may be rigid (e.g. rigid PCB) or flexible substrate (e.g. flexiblePCB, or redistribution layer formed using thing film processing). Asshown in FIG. 17A-17C, the routing layer 130 may include one or morewiring layers 144, dielectric layers 142, and vias 146. Routing contacts148 can be exposed on the top side 136, bottom side 138 and a mountingsurface within cavity 190. Conductive bumps 404 (e.g. solder) can beapplied to the routing contacts 148 within the cavity 190 followed bymounting of the transducer 400, or alternatively, conductive bumps 404can be attached to the transducer 400 prior to mounting of thetransducer 400 within the cavity 190. The transducer 400 can be alsodipped in paste or flux prior to placement into the cavity to reducemanufacturing complexity.

Referring now to FIG. 17D, an insulating layer 430 is applied around thetransducer 400 within the cavity 190 to encapsulate the transducer 400,optionally leaving a surface 401 exposed. An optical window 420 is thenformed over the transducer 400 at operation 1630. As shown in FIG.17E-17F, formation of the optical window may include forming a layer ofthe optical window 420 (which can include a single layer, or stack ofmultiple layers), followed by formation of a dielectric coating 410around the optical window 420. Additional components can the be mountedon the opposite side (e.g. top side) of the routing layer 130 atoperation 1640 as shown in FIG. 17G. This may be followed by integrationof an enclosure or additional encapsulation/molding to form the packageillustrated in FIG. 15.

In the following description of FIGS. 18 and 21, temperature sensorpackage 100 variations are described and illustrated that share similarfeatures to that of the embodiment described an illustrated with regardto FIG. 1 such as a routing layer 130 that includes a chip contact area132 and a touch area 134 adjacent to the chip contact area 132.Referring now to the embodiment illustrated in FIG. 18, the routinglayer 130 may include a rigid-flex connection 1800, in which the chip110 is mounted on the rigid portion 1810 of the rigid-flex connectionand the electrically conductive sensor pattern 120 spans over flexibleportion 1820 of the rigid-flex connection. Similar to previousdescriptions of the routing layers 130, the rigid flex connection 1800may include one or more dielectric layers 142 and wiring layers 144. Therigid portion 1810 may include different dielectric layers than theflexible portion 1820 and/or additional layers such as glass cloth, etc.to provide rigidity. As shown, a top side metallization layer(s) may beused to form both a top side wiring layer 144 and electricallyconductive sensor pattern 120 on a top side of the rigid-flex connection1800.

FIG. 19 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 18 in accordance with an embodiment. FIGS.20A-20C are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 18 inaccordance with an embodiment. In interest of clarity and concisenessthe processing sequences of FIGS. 19 and 20A-20C are describedconcurrently. At operation 1910 a top side metallization layer includinga wiring layer 144 and electrically conductive sensor pattern 120 isformed on a rigid-flex connection 1800. The top side metallization layermay be formed using any suitable technique, such as plating(electroplating, electroless plating), printing, dispensing, etc. Asshown in FIG. 20A the top side metallization layer spans both the rigidportion 1810 and flexible portion 1820 of the rigid-flex connection1800. A chip 110 is then mounted onto the top side metallization layeron the rigid portion 1810 as shown in FIG. 20B, followed byencapsulation with an insulating layer 140 at operation 1930 as shown inFIG. 20C.

Referring now to the embodiment illustrated in FIG. 21, the routinglayer 130 may be formed on a single substrate 300. For example,substrate 300 may be a flexible insulating material, such as anelectrical grade polymer such as polyimide. Routing layer 130 may be atop side metallization layer(s) including both wiring layer 144 and theelectrically conductive sensor pattern 120. The top side metallizationlayer may be formed using any suitable technique, such as plating(electroplating, electroless plating), printing, dispensing, etc.

FIG. 22 is a flow diagram of a method of fabricating the temperaturesensor package of FIG. 21 in accordance with an embodiment. FIGS.23A-23D are schematic cross-sectional side view illustrations of amethod of fabricating the temperature sensor package of FIG. 21 inaccordance with an embodiment. In interest of clarity and concisenessthe processing sequences of FIGS. 22 and 23A-23D are describedconcurrently. At operation 2210 a top side metallization layer includinga wiring layer 144 and electrically conductive sensor pattern 120 isformed on the substrate 300. The top side metallization layer may beformed using any suitable technique, such as plating (electroplating,electroless plating), printing, dispensing, etc. As shown in FIGS.23A-3B, the substrate 300 may first be formed onto a rigid carriersubstrate. For example, this may be accomplished by lamination,deposition, dispensing, etc. The top side metallization layer is thenformed using a variety of techniques such as screen printing or otherdispensing method, physical or chemical vapor deposition, and plating.Screen printing or other dispensing methods in particular may beparticularly simple for manufacturing. The chip 110 is then mounted ontothe wiring layer 144 at operation 2210 as shown in FIG. 23C, followed byremoval of the rigid carrier substrate 200 as shown in FIG. 23D.

FIGS. 24-26 illustrate various wearable health devices in which thevarious embodiments can be implemented. These illustrations are intendedto be exemplary and non-exhaustive implementations. FIGS. 24-25 areschematic side view illustrations of portable electronic devices such asearbuds 2400 in accordance with embodiments that include a housing 2402and one or more temperature sensor packages 100 described herein. Forexample, an IR temperature sensor package 100 such as that described andillustrated with regard to FIG. 15 can be aligned with an opening 2410in the housing for non-contact temperature sensing. Specifically, theoptical window 420 may aligned with opening 2410. In otherconfigurations, any of the touch sensitive temperature sensor packages100 described herein can be arranged within, on, or aligned with asurface of the housing 2402 for touch sensing. FIG. 26 is a schematicside view illustration of a wearable device 2600 in which a temperaturesensor package 100 secured within a fabric 2602. For example, the fabriccan be integrated into a piece of clothing such as shirt, headband,glove, strap, etc.

In utilizing the various aspects of the embodiments, it would becomeapparent to one skilled in the art that combinations or variations ofthe above embodiments are possible for forming temperature sensorpackages. Although the embodiments have been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that the appended claims are not necessarily limited to thespecific features or acts described. The specific features and actsdisclosed are instead to be understood as embodiments of the claimsuseful for illustration.

What is claimed is:
 1. A temperature sensor package comprising: arouting layer; a chip mounted face down on the routing layer; aninsulating layer encapsulating the chip on the routing layer; aplurality of through vias through the insulating layer; and anelectrically conductive sensor pattern over the insulating layer andcoupled to the plurality of through vias.
 2. The temperature sensorpackage of claim 1, wherein the electrically conductive sensor patternis directly over a back side of the chip.
 3. The temperature sensorpackage of claim 1, wherein the chip is solder bonded to the routinglayer.
 4. The temperature sensor package of claim 1, wherein at least aportion of the electrically conductive temperature sensor pattern and atleast one of the plurality of through vias is formed of a same material.5. The temperature sensor package of claim 4, wherein the same materialcomprises coalesced metallic particles forming the portion of theelectrically conductive temperature sensor pattern and the one of theplurality of through vias.
 6. The temperature sensor package of claim 1:wherein the insulating layer is a laser direct structuring (LDS)compatible material including a dispersed non-conductive metal organiccompound; and wherein the plurality of vias include a nucleation layerof metal particles of the metal in the dispersed non-conductive metalorganic compound.
 7. The temperature sensor package of claim 6, whereinthe electrically conductive sensor pattern includes a nucleation layerpattern of metal particles of the metal in the dispersed non-conductivemetal organic compound.
 8. The temperature sensor package of claim 1,wherein the electrically conductive sensor pattern is a thermocouplepattern including a first pattern of a first conductive material and asecond pattern of a second conductive material different from the firstconductive material.
 9. The temperature sensor package of claim 8,wherein the plurality of through vias includes a first via connected tothe first pattern, and a second via connected to the second pattern. 10.The temperature sensor package of claim 9, wherein the first viacomprises the first conductive material, and the second via comprisesthe second conductive material.
 11. The temperature sensor package ofclaim 1, wherein the electrically conductive sensor pattern is aresistance temperature detector (RTD) pattern.
 12. The temperaturesensor package of claim 11, wherein the RTD pattern is formed of adifferent material than the plurality of through vias.
 13. Thetemperature sensor package of claim 1, secured within a portableelectronic device.
 14. The temperature sensor package of claim 1,secured to a fabric of a wearable device.
 15. A temperature sensorpackage comprising: a routing layer including: a chip contact area; anda touch area adjacent the chip contact area, the touch area including anelectrically conductive sensor pattern electrically connected to thechip contact area; and a chip bonded to the routing layer in the chipcontact area.
 16. The temperature sensor package of claim 15, whereinthe chip is encapsulated in an insulating layer laterally surroundingthe chip on a top side of the routing layer, wherein the insulatinglayer spans the touch area.
 17. The temperature sensor package of claim16, wherein the chip is mounted on a first side of the routing layer,and a second side of the routing layer opposite the first side includesthe electrically conductive sensor pattern.
 18. The temperature sensorpackage of claim 15, wherein the routing layer comprises a rigid-flexconnection, the chip is mounted on a rigid portion of the rigid-flexconnection and the electrically conductive sensor pattern is part of aflexible portion of the rigid-flex connection.
 19. A temperature sensorpackage comprising: a routing layer including a top side and a bottomside; a cavity formed in the bottom side of the routing layer; atransducer mounted within the cavity; a chip mounted on the top side ofthe routing layer and in electrical connection with the transducer. 20.The temperature sensor of claim 19, further comprising an optical windowover a surface of the transducer.
 21. The temperature sensor of claim20, further comprising an insulating layer encapsulating the routinglayer and the chip.